/*
 * contrib/btree_gist/btree_utils_num.c
 */
#include "postgres.h"

#include "btree_gist.h"
#include "btree_utils_num.h"
#include "utils/cash.h"
#include "utils/date.h"
#include "utils/timestamp.h"


GISTENTRY *
gbt_num_compress(GISTENTRY *entry, const gbtree_ninfo *tinfo)
{
    GISTENTRY  *retval;

    if (entry->leafkey)
    {
        union
        {
            int16        i2;
            int32        i4;
            int64        i8;
            float4        f4;
            float8        f8;
            DateADT        dt;
            TimeADT        tm;
            Timestamp    ts;
            Cash        ch;
        }            v;

        GBT_NUMKEY *r = (GBT_NUMKEY *) palloc0(tinfo->indexsize);
        void       *leaf = NULL;

        switch (tinfo->t)
        {
            case gbt_t_int2:
                v.i2 = DatumGetInt16(entry->key);
                leaf = &v.i2;
                break;
            case gbt_t_int4:
                v.i4 = DatumGetInt32(entry->key);
                leaf = &v.i4;
                break;
            case gbt_t_int8:
                v.i8 = DatumGetInt64(entry->key);
                leaf = &v.i8;
                break;
            case gbt_t_oid:
            case gbt_t_enum:
                v.i4 = DatumGetObjectId(entry->key);
                leaf = &v.i4;
                break;
            case gbt_t_float4:
                v.f4 = DatumGetFloat4(entry->key);
                leaf = &v.f4;
                break;
            case gbt_t_float8:
                v.f8 = DatumGetFloat8(entry->key);
                leaf = &v.f8;
                break;
            case gbt_t_date:
                v.dt = DatumGetDateADT(entry->key);
                leaf = &v.dt;
                break;
            case gbt_t_time:
                v.tm = DatumGetTimeADT(entry->key);
                leaf = &v.tm;
                break;
            case gbt_t_ts:
                v.ts = DatumGetTimestamp(entry->key);
                leaf = &v.ts;
                break;
            case gbt_t_cash:
                v.ch = DatumGetCash(entry->key);
                leaf = &v.ch;
                break;
            default:
                leaf = DatumGetPointer(entry->key);
        }

        Assert(tinfo->indexsize >= 2 * tinfo->size);

        memcpy((void *) &r[0], leaf, tinfo->size);
        memcpy((void *) &r[tinfo->size], leaf, tinfo->size);
        retval = palloc(sizeof(GISTENTRY));
        gistentryinit(*retval, PointerGetDatum(r), entry->rel, entry->page,
                      entry->offset, FALSE);
    }
    else
        retval = entry;

    return retval;
}

/*
 * Convert a compressed leaf item back to the original type, for index-only
 * scans.
 */
GISTENTRY *
gbt_num_fetch(GISTENTRY *entry, const gbtree_ninfo *tinfo)
{
    GISTENTRY  *retval;
    Datum        datum;

    Assert(tinfo->indexsize >= 2 * tinfo->size);

    /*
     * Get the original Datum from the stored datum. On leaf entries, the
     * lower and upper bound are the same. We just grab the lower bound and
     * return it.
     */
    switch (tinfo->t)
    {
        case gbt_t_int2:
            datum = Int16GetDatum(*(int16 *) entry->key);
            break;
        case gbt_t_int4:
            datum = Int32GetDatum(*(int32 *) entry->key);
            break;
        case gbt_t_int8:
            datum = Int64GetDatum(*(int64 *) entry->key);
            break;
        case gbt_t_oid:
        case gbt_t_enum:
            datum = ObjectIdGetDatum(*(Oid *) entry->key);
            break;
        case gbt_t_float4:
            datum = Float4GetDatum(*(float4 *) entry->key);
            break;
        case gbt_t_float8:
            datum = Float8GetDatum(*(float8 *) entry->key);
            break;
        case gbt_t_date:
            datum = DateADTGetDatum(*(DateADT *) entry->key);
            break;
        case gbt_t_time:
            datum = TimeADTGetDatum(*(TimeADT *) entry->key);
            break;
        case gbt_t_ts:
            datum = TimestampGetDatum(*(Timestamp *) entry->key);
            break;
        case gbt_t_cash:
            datum = CashGetDatum(*(Cash *) entry->key);
            break;
        default:
            datum = PointerGetDatum(entry->key);
    }

    retval = palloc(sizeof(GISTENTRY));
    gistentryinit(*retval, datum, entry->rel, entry->page, entry->offset,
                  FALSE);
    return retval;
}



/*
** The GiST union method for numerical values
*/

void *
gbt_num_union(GBT_NUMKEY *out, const GistEntryVector *entryvec, const gbtree_ninfo *tinfo, FmgrInfo *flinfo)
{
    int            i,
                numranges;
    GBT_NUMKEY *cur;
    GBT_NUMKEY_R o,
                c;

    numranges = entryvec->n;
    cur = (GBT_NUMKEY *) DatumGetPointer((entryvec->vector[0].key));


    o.lower = &((GBT_NUMKEY *) out)[0];
    o.upper = &((GBT_NUMKEY *) out)[tinfo->size];

    memcpy((void *) out, (void *) cur, 2 * tinfo->size);

    for (i = 1; i < numranges; i++)
    {
        cur = (GBT_NUMKEY *) DatumGetPointer((entryvec->vector[i].key));
        c.lower = &cur[0];
        c.upper = &cur[tinfo->size];
        /* if out->lower > cur->lower, adopt cur as lower */
        if ((*tinfo->f_gt) (o.lower, c.lower, flinfo))
            memcpy((void *) o.lower, (void *) c.lower, tinfo->size);
        /* if out->upper < cur->upper, adopt cur as upper */
        if ((*tinfo->f_lt) (o.upper, c.upper, flinfo))
            memcpy((void *) o.upper, (void *) c.upper, tinfo->size);
    }

    return out;
}



/*
** The GiST same method for numerical values
*/

bool
gbt_num_same(const GBT_NUMKEY *a, const GBT_NUMKEY *b, const gbtree_ninfo *tinfo, FmgrInfo *flinfo)
{
    GBT_NUMKEY_R b1,
                b2;

    b1.lower = &(((GBT_NUMKEY *) a)[0]);
    b1.upper = &(((GBT_NUMKEY *) a)[tinfo->size]);
    b2.lower = &(((GBT_NUMKEY *) b)[0]);
    b2.upper = &(((GBT_NUMKEY *) b)[tinfo->size]);

    return ((*tinfo->f_eq) (b1.lower, b2.lower, flinfo) &&
            (*tinfo->f_eq) (b1.upper, b2.upper, flinfo));
}


void
gbt_num_bin_union(Datum *u, GBT_NUMKEY *e, const gbtree_ninfo *tinfo, FmgrInfo *flinfo)
{
    GBT_NUMKEY_R rd;

    rd.lower = &e[0];
    rd.upper = &e[tinfo->size];

    if (!DatumGetPointer(*u))
    {
        *u = PointerGetDatum(palloc0(tinfo->indexsize));
        memcpy((void *) &(((GBT_NUMKEY *) DatumGetPointer(*u))[0]), (void *) rd.lower, tinfo->size);
        memcpy((void *) &(((GBT_NUMKEY *) DatumGetPointer(*u))[tinfo->size]), (void *) rd.upper, tinfo->size);
    }
    else
    {
        GBT_NUMKEY_R ur;

        ur.lower = &(((GBT_NUMKEY *) DatumGetPointer(*u))[0]);
        ur.upper = &(((GBT_NUMKEY *) DatumGetPointer(*u))[tinfo->size]);
        if ((*tinfo->f_gt) ((void *) ur.lower, (void *) rd.lower, flinfo))
            memcpy((void *) ur.lower, (void *) rd.lower, tinfo->size);
        if ((*tinfo->f_lt) ((void *) ur.upper, (void *) rd.upper, flinfo))
            memcpy((void *) ur.upper, (void *) rd.upper, tinfo->size);
    }
}



/*
 * The GiST consistent method
 *
 * Note: we currently assume that no datatypes that use this routine are
 * collation-aware; so we don't bother passing collation through.
 */
bool
gbt_num_consistent(const GBT_NUMKEY_R *key,
                   const void *query,
                   const StrategyNumber *strategy,
                   bool is_leaf,
                   const gbtree_ninfo *tinfo,
                   FmgrInfo *flinfo)
{
    bool        retval;

    switch (*strategy)
    {
        case BTLessEqualStrategyNumber:
            retval = (*tinfo->f_ge) (query, key->lower, flinfo);
            break;
        case BTLessStrategyNumber:
            if (is_leaf)
                retval = (*tinfo->f_gt) (query, key->lower, flinfo);
            else
                retval = (*tinfo->f_ge) (query, key->lower, flinfo);
            break;
        case BTEqualStrategyNumber:
            if (is_leaf)
                retval = (*tinfo->f_eq) (query, key->lower, flinfo);
            else
                retval = ((*tinfo->f_le) (key->lower, query, flinfo) &&
                          (*tinfo->f_le) (query, key->upper, flinfo));
            break;
        case BTGreaterStrategyNumber:
            if (is_leaf)
                retval = (*tinfo->f_lt) (query, key->upper, flinfo);
            else
                retval = (*tinfo->f_le) (query, key->upper, flinfo);
            break;
        case BTGreaterEqualStrategyNumber:
            retval = (*tinfo->f_le) (query, key->upper, flinfo);
            break;
        case BtreeGistNotEqualStrategyNumber:
            retval = (!((*tinfo->f_eq) (query, key->lower, flinfo) &&
                        (*tinfo->f_eq) (query, key->upper, flinfo)));
            break;
        default:
            retval = false;
    }

    return (retval);
}


/*
** The GiST distance method (for KNN-Gist)
*/

float8
gbt_num_distance(const GBT_NUMKEY_R *key,
                 const void *query,
                 bool is_leaf,
                 const gbtree_ninfo *tinfo,
                 FmgrInfo *flinfo)
{
    float8        retval;

    if (tinfo->f_dist == NULL)
        elog(ERROR, "KNN search is not supported for btree_gist type %d",
             (int) tinfo->t);
    if (tinfo->f_le(query, key->lower, flinfo))
        retval = tinfo->f_dist(query, key->lower, flinfo);
    else if (tinfo->f_ge(query, key->upper, flinfo))
        retval = tinfo->f_dist(query, key->upper, flinfo);
    else
        retval = 0.0;

    return retval;
}


GIST_SPLITVEC *
gbt_num_picksplit(const GistEntryVector *entryvec, GIST_SPLITVEC *v,
                  const gbtree_ninfo *tinfo, FmgrInfo *flinfo)
{
    OffsetNumber i,
                maxoff = entryvec->n - 1;
    Nsrt       *arr;
    int            nbytes;

    arr = (Nsrt *) palloc((maxoff + 1) * sizeof(Nsrt));
    nbytes = (maxoff + 2) * sizeof(OffsetNumber);
    v->spl_left = (OffsetNumber *) palloc(nbytes);
    v->spl_right = (OffsetNumber *) palloc(nbytes);
    v->spl_ldatum = PointerGetDatum(0);
    v->spl_rdatum = PointerGetDatum(0);
    v->spl_nleft = 0;
    v->spl_nright = 0;

    /* Sort entries */

    for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
    {
        arr[i].t = (GBT_NUMKEY *) DatumGetPointer((entryvec->vector[i].key));
        arr[i].i = i;
    }
    qsort_arg((void *) &arr[FirstOffsetNumber], maxoff - FirstOffsetNumber + 1, sizeof(Nsrt), (qsort_arg_comparator) tinfo->f_cmp, (void *) flinfo);

    /* We do simply create two parts */

    for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
    {
        if (i <= (maxoff - FirstOffsetNumber + 1) / 2)
        {
            gbt_num_bin_union(&v->spl_ldatum, arr[i].t, tinfo, flinfo);
            v->spl_left[v->spl_nleft] = arr[i].i;
            v->spl_nleft++;
        }
        else
        {
            gbt_num_bin_union(&v->spl_rdatum, arr[i].t, tinfo, flinfo);
            v->spl_right[v->spl_nright] = arr[i].i;
            v->spl_nright++;
        }
    }

    return v;
}
